Method of making cast boxes



June 22, 1965 M. G. zAvl-:RTNIK r-:TAL 3,189,955

METHOD OF MAKING CAST BOXES I Filed Aug. 26, 1965 2 Sheets-Sheet l CLARENCE H. fem/651g' mfmw A T To RNEr/s June 22, 1955 M. G. zAvl-:RTNIK ETAL 3,189,955

METHOD OF MAKING CAST BOXES Filed Aug. 26, 1963 2 Sheets-Sheet 2 /A/VEA/Toe: MQRSHALL 6.2AV5RTN/K, CLARENCE H. Ro/61E);

Arrow/EVS United States Patent 3 139 95S Murr-ron or risulta@ naar noxes Marshall G. Zavertnilr, Manchester, Mo., and Clarence H.

Rongey, Granite City, lli., assignors to liiiark Eiectric Manufacturing Company, St. Louis, Mo., a corporation of Missouri Filed Aug. 26, i963, Ser. No. 3534,452

y 7 Claims. (Cl. Zin-B) The present invention relates to a method of making cast boxes and molds for such boxes. Such boxes are capable of use in a number of connections but are particularly useful in areas where there is an explosive or combustible atmosphere, as junction boxes that can be made dust tight and explosion-proof, so that they can enclose electrical equipment that is subject to sparking.

Such boxes are required in many cases to have inturned or out-turned flanges on the top, sometimes with upstanding rims on the flanges. Heretofore it has been customary to fabricate these boxes from sheet metal, then weld, grind, drill, tap and llnish them. Such fabricated boxes are costly, less strong and rigid, and more likely to fail to be explosion-proof than is the box made by the present method. Yet prior casting of such boxes has been excessively expensive, since it has required the use of baked cores or the like. It is a principal object of the present invention to provide a method of manufacturing a mold for casting such boxes, and particularly to provide such a method that does not involve the use of baked cores.

It is a further object of the invention to provide a method of this kind that has a minimum number of` mold parts for a maximum variety of boxes, which may differ in depth and in top flange construction.

Basically, the present invention involves the parting of the mold at the top of the sidewall of the box. The iiange mold is formed in a drag and the box mold is formed in a cope. The box mold includes a green sand core resting on top of the drag mold.

This arrangement enables the flanging pattern to be formed as part of or attached to one side of a pattern plate. Therefore different flange patterns can be used with any correspondingly sized box pattern. VThe arrangement also enables the same pattern plate to have one kind of flange pattern on `one face and a different kind of a llanging pattern on its opposite face. In such ways, the presentsystem reduced the amount of equipment required for a complete line of boxes.

Another feature of the present invention lies in the fact that with the box section having straight vertical sides, boxes of different depths can be made from the same box pattern by the expedient of having inserts and ring plates that constitute supplemental parts for the pattern to make it different in eective depth.

Other objects and features of the invention will appear from the description of the process to follow.

In the drawings:

FIGURE l is a perspective view of a box made in accordance with the present method;

FIGURE 2 is a characteristic longitudinal section through the box of FIGURE 1;

FIGURE 3 is a fragmentary section similar to the left side of FIGURE 2 but with a different type of top llanging, this flange being turned outwardly;

FIGURE 4 is a view similar to FIGURE 3, but with the lianging extending outwardly and then upwardly;

FIGURE 5 is a `view similar to FIGURE 3` but with the llanging turned inwardly;

FIGURE 6 is a View partly in section showing a match plate with a ilange pattern on each of its opposite sides; FIGURE 7 is a view of a drag mold made in accordance with one of the flanged patterns of FIGURE 6;

FiGURi-l 8 is a fragmentary View of another pattern plate similar to that or" FIGURE 6 but with different flange patterns;

FIGURE 9 is a view of a step in the manufacture of a green sand core for the box;

FIG. l() is a view of a stage in the process of making the mold wherein the green sand core has been applied to the r'lange mold shown in FIGURE 7;

FIGURE 1l is a view showing the manufacture of the principal box mold in the cope;

FIGURE 12 is a view showing the stage at which the box mold in the cope, after the pattern has been drawn, has been applied and matched to the flange mold in the drag;

FlGURE 13 is a view of the manufacure of `a box mold on a pattern where it is desired to reduce the depth of the box; and

FIGURE 14 is a View of the manufacture of the green sand core for the box using the deep pattern but producing a shallow core for a shallower box.

As illustrated in FlGURE l, the box 2lb, is, generally speaking, rectangular in cross-section. It can have other shapes, but should not have undercut side walls below the flanges. FIGURE 2 shows this same box in longitudinal cross-section, as having an inturned ilange 21 around the top, the inner rim of which extends upwardly as shown at 22. Feet 23 may be applied separately to the box.

In order to cast a box with an inturned flange, such as is illustrated in FIGURE 2, it has heretofore been conventional to use a baked core which is destroyed after the casting is made. rlhe present invention makes the box with a wholly green sand mold.

The first stage in the manufacture of the mold includes the making of a flange mold in a drag, such as the one as illustrated in FIGURE 7. To make this mold, a match plate 3u, or the like, can have a flange pattern 3l mounted on one of its faces. A dilferent flange pattern 32 is mounted on the opposite plate.

With the plate 3h resting on some support and forming a bottom, the drag 353 is mounted over the plate 3? and suitably located by familiar matching means. Sand 334i is then rammed into the drag 33 around the pattern 3T.. The foregoing would be similar to, but inverted from the position illustrated in FIGURE 7.

After the sand is suitably rammed, the pattern, sand and drag assembly is reverted to the position of FIG- URE 7, and the pattern is drawn as is suggested by the dashed lines between FlGURE 6 and FIGURE 7, leaving a flanged mold cavity as it appears in FIGURE 7. This cavity is usually a complete, closed rectangle, leaving an island surrounded by the channel-like cavity.

If the match plate Ell is inverted, so that the pattern 32 formed the cavity, the flanging illustrated in FIGURE 4 will result. if the match plate 37 illustrated in FIG- URE 8 is used, with the pattern 33, the anging of FIG- RE 5 will be formed. If the plate 37 is used with the pattern 3Q, the flanging of FGURE 3 will ybe formed.

'In any case, after the drag `mold has been formed as illustrated, then `a green sand core is formed from the box pattern. This is illustrated in FIGURE 9. A hollow box pattern ft2, which has the shape of the ultimate box below the tlange, is lilled with sand 43 and rammed. A plate lf-i is then applied over it and 'the cope mold is reverted. It is lifted from the plate tl-t, `and placed over the drag mold of FlGUlE 7, resting upon .the sand at the par-ting line, and on the island within the flange cavity. As illustrated, it overhangs the flange cavity. Thereupon the pattern @E is withdrawn, leaving the green sand core z3 in pla-ce over the drag mold, as appears in FIGURE l0. (We note that it is to be understood that Yiitted and raised above `the plate 55 'by spacers 58.

appropriate draft provisions .are made to enable the various patterns to be drawn.)

The next Vstep is to insert the box pattern 42 into a cope d@ on a plate S7 as is illustrated in FIGURE 1l,

closed end up. Sand 43 is then rammed around and over the pattern d2. This assembly is then .inverted and the pattern 42, drawn, leaving the box mold cavity in the cope 46. The cope mold is then reverted and applied Yto the drag mold of FGURE 7, as appears'in FEGURE -like,but rather that can be made wholly from green sand. The box can have overhanging flanges. Also, a single box mold and pattern can be use with various flange patterns to provide the box with any selected hanging arrangement without requiring additional coring or `addi-tional patterns.

As shown in FIGURES 13 .and 14, the same patterns can be used to make boxes of dierent heights. The box pattern d2 inFlGURE 13 is shown upon a plate Se. Around the pattern a supplemental ring plate 57 is The cope 45 irests upon the ring 57. ln this case the box cavity in the sand 6@ is of less depth than in FIGURE 1l, yalthough .the pattern 42'is the same, and the length, breadth, and wall thicknesses, remain the same. For this arrangement, the green sand core must be shallower.

.This is shown in FIGURE 14- as being made from the same box pattern 42, but with a supplemental bottom plate o2 therein, spaced from the bottom of the `pattern 42 by spacers 163.V lThis gives a box green sand core 6d shallower than would otherwise be provided, and appropriate to the box mold dit.

By the supplemental ring 57 and the plate 62, the basic patternl can be used for many different depths of boxes, from quite shallow to quite deep. lt is necessary to make nthe main pattern of `the maximum depth and then to provide only the `ring S7 and plate 62 with dilierent spacers 58 and 63, to obtain -a full line of boxes of this length and breadth, but of various depths. And any top flange pattern may be used for making any depth of box.

This method of molding not only makes a superior box, as set forth in an accompanying application, but Valso provides for many Variations of a basic box, with `a minimum of pattern parts.

Various changes and modilications may be made within the process of this invention as will be readily apparen-t to those skilled in the art. Such changes and modiications Iare Within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

l.- In a method of molding a box that has a bottom, generally vertical side walls, .and an overhanging flange on the side walls extending laterally therefrom, the steps of: making a flange mold by placing a drag onto a match plate having a rigid flange pattern thereon, which flange pattern has the shape of the box walls including the flange and yabove the same, and packing sand into the drag `around the pattern and against the plate, removing the plate and dra-wing the pattern, thereby providing a mold having .a flange cavity opening into its upper surface; forming in a box-like pattern a green sand core shaped llike the interior side and bottom walls of the box below the flange, applying the same onto the flange mold to rest on the same inside the flange cavity, and drawing the pattern ofi? the core; forming a side and bottom =wall mold by packing sand around the sides and end, fa rigid :box-like pattern in a cope, which pattern is eases shaped to form the outside of the side and bottom walls of the box and drawing the pattern to leave Ithe cavity in the cope; inverting the said c-ope over the previously formed core and applying it to the ange mold, in proper alignment therewith; the side wall mold and the core within it forming a side Wall cavity that registers lwith and opens into the flange cavity, the steps set forth forming a mold for a box having unitary bottom, side and flange walls.

`2. In the method of claim 1, the steps of: forming the flange mold lcavity of a shape that extends inwardly from the portions that `form the box wall mold cavities, for .the purpose of forming an irl-turned top flange on the box.

3. ln the method of claim i, the steps of: forming a liange mold cavity that is vangular in cross-section, having `a cavity portion that extends vertically, and a cavity Vportion that extends laterally from the vertical position, Athe vertically extending portion forming a wall part on 'the box above the flange.

d. In the method of claim 1, the steps of forming the green sand core in a hollow box pattern, that is then open at the top, then inverting the pattern containing the sand, applying the assembly over the ange mold and Ialigning it therewith, withdrawing the pattern, and thereafter completing the mold as aforesaid.

5. In the method of claim 1, the steps of: forming the box mold cavity by packing sand in a mold frame around sand above the outside of the same box pattern, then inverting the mold frame with the sand and pat-tern, withdrawing .the pattern, and reverting the mold thus formed over the core and flange cavity, and matching them.

6. In the method of claim 1: the steps of inserting a plate in :the box-like core pattern to form a false bottom thereto that is spaced from the normal bottom of the pattern, so .that the core is `shallower than .the depth of the pattern, and in making the cavity for the side and bottom wall mold, the added steps of applying a ring around the outside of lthe tbox-like pattern adjacent the open end, and resting the cope on this ring, so that the cavity has a depth less .than that of the pattern; these steps producing a mold for a shallow box from deep box patterns.

'7. A mold `for a box having bot-tom -and side walls, and flanges extending laterally at the top of the side walls; the mold being formed in two mold frames, the

frames partingV the cavity below the laterally extending flanges; the lower frame having mold-forming material forming a `flange cavity, and a convex green sand core `portion for forming the interior walls of thebox below the flange, which green sand core portion is disposedV upon `and rises from the mold-forming material inside the ange cavity yand above the parting; an upper frame resting upon the lower frame having mold-forming material forming a box cavity shaped to the lsize of the outside Wall surfaces of the box below the flange; the upper frame disposing its cavity over the convex green sand portion :and in registry with the liange cavity, the flange' cavity consisting of a channel extending around the top` of the mold-forming material, .at-the top of said material, with an island of the material within .the channel, the convex core portion resting upon the said island, and overhanging the channel.

References Cited by the llxarninerV UNITED STATES PATENTS 32,399 5/ 61 Hurlburt 22-198 1,882,652 10/32 Schmiedenech-t 26--163 XR 2,129,570 9/38 Dooley 22-l93 XR 3,010,166 11/61 Skoning 22-193 MICHAEL V. BRENDlSl, Primary Examiner. 'MARCUS U. LYONS, Examiner. 

1. IN A METHOD OF MOLDING A BOX THAT HAS A BOTTOM, GENERALLY VERTICAL SIDE WALLS, AND AN OVERHANGING FLANGE ON THE SIDE WALLS EXTENDING LATERALLY THEREFROM, THE STEPS OF: MAKING A FLANGE MOLD BY PLACING A DRAG ONTO A MATCH PLATE HAVING A RIGID FLANGE PATTERN THEREON, WHICH FLANGE PATTERN HAS THE SHAPE OF THE BOX WALLS INCLUDING THE FLANGE AND ABOVE THE SAME, AND PACKING SAND INTO THE DRAG AROUND THE PATTERN AND AGAINST THE PLATE, REMOVING THE PLATE AND DRAWING THE PATTERN, THEREBY PROVIDING A MOLD HAVING A FLANGE CAVITY OPENING INTO ITS UPPER SURFACE; FORMING IN A BOX-LIKE PATTERN A GREEN SAND CORE SHAPED LIKE THE INTERIOR SIDE AND BOTTOM WALLS OF THE BOX BELOW THE FLANGE, APPLYING THE SAME ONTO THE FLANGE MOLD TO REST ON THE SAME INSIDE THE FLANGE CAVITY, AND DRAWING THE PATTERN OFF THE CORE; FORMING A SIDE AND BOTTOM WALL MOLD BY PACKING SAND AROUND THE SIDES AND END, A RIGID BOX-LIKE PATTERN IN A COPE, WHICH PATTERN IS SHAPED TO FORM THE OUTSIDE OF THE SIDE AND BOTTOM WALLS OF THE BOX AND DRAWING THE PATTERN TO LEAVE THE CAVITY IN THE COPE; INVERTING THE SAID COPE OVER THE PREVIOUSLY FORMED CORE AND APPLYING IT TO THE FLANGE MOLD, IN PROPER ALIGNMENT THEREWITH; THE SIDE WALL MOLD AND THE CORE WITHIN IT FORMING A SIDE WALL CAVITY THAT REGISTERS WITH AND OPENS INTO THE FLANGE CAVITY, THE STEPS SET FORTH FORMING A MOLD FOR A BOX HAVING UNITARY BOTTOM, SIDE AND FLANGE WALLS. 